Engineer
believes the danger of icebergs is underestimatedTitanic’s lesson being forgotten

By
Michelle Osmond

Icebergs,
like this piece lurking near the Ocean Science Centre,
are still a great danger to ships.

The Titanic disaster is far enough in the past that people
are forgetting the lessons of that tragedy, says Dr. Claude
Daley, professor and chair of Ocean and Naval Architectural
Engineering. Not only is the risk of a ship being destroyed
by an iceberg still present, he said, but it may be even higher.

Dr. Daley, who is also the director of the Ocean Engineering
Research Centre at Memorial, recently finished a report titled
A Study of the Process-Spatial Link in Ice Pressure-Area
Relationships for the Program on Energy Research and Development
(managed by the National Research Council of Canada).
He concludes that in large scale collisions the ice forces
– the amount of pressure exerted by the ice on the hull
of a ship, for example – are likely being significantly
underestimated.

Dr. Daley says ships today are better built, but are still
not strong enough to withstand a collision with a large iceberg.

“People believe shipbuilding has evolved to the point
where it can't happen again,” he said. “Studies
have suggested that Titanic’s steel was much
weaker and more brittle than modern steel. But, of course,
nobody measured the ice loads on the Titanic. We don't really
know how strong the Titanic should have been to survive that
iceberg collision.

“I doubt if any ship afloat today, even one the size
of Titanic, would survive such a collision without
major flooding.”

The increased risk, Dr. Daley noted, comes from an apparent
trend that can be seen in all plots of ice load data. He says
the trend has been normally interpreted to mean that the ice
gets softer as a collision progresses. “We ice specialists
have talked ourselves into the concept of ‘softening
ice’ and I'm beginning to think we've made a gross error,”
he explained. “When I examined the data more closely,
looking at the internal trends in the data, a very different
result emerged. In fact the ice seems to get stronger as the
collision progresses. This would result in much higher force
predictions for large collisions.”

Bruce Colbourne, senior research officer with the National
Research Council of Canada Institute for Ocean Technology,
disagrees with Dr. Daley’s theories, however. He admits
that although the risk has not gone away he says it is not
greater than it was in the time of the Titanic.

“The damage sustained in any collision depends on many
factors – one of which is the strength of the object
you hit. However, other things, such as the speed at which
you hit it, are equally important. Both our knowledge of the
important parameters and the technology available to deal
with them has improved since 1912. Just the introduction of
radar has
virtually eliminated ship collisions with large icebergs as
they can now be detected, and avoided.” He says it would
be too expensive to build a ship to withstand a collision
unlikely to occur.

“This would be akin to designing all cars to withstand
frontal impacts with transport trucks. Better to invest in
technology to avoid the collision and operate the vessel prudently
when in areas where ice may be present.”

Mr. Colborne agreed that knowledge of ice strength could be
improved. “There is considerable scatter in the available
data and many interpretations of why this is and what it means.
Dr. Daley has an interpretation of a particular strength effect
that may illuminate one important piece of the puzzle. However,
if a 20,000 tonne ship runs square into a 100,000 tonne iceberg
at 16 knots, it will make very little difference to the damage
sustained by the vessel whether the ice gets a little harder
or a little softer as the collision progresses. It will still
be one heck of a collision.”